The composition and diversity of bacterial community in Megalobrama amblycephala intensive rearing pond sediments were investigated by PCR-DGGE(denaturing gradient gel electrophoresis)and DNA sequencing technology.Sediments were collected at different depths(0-10 cm,10-20 cm,20-30 cm,30-40 cm)during non-feeding period.The structure feature displayed high levels in the richness of microbial communities(38)and Shannon-Wiener index(3.18).This represented that the Megalobrama amblycephala intensive rearing pond had a high microbial variety.The Shannon-Weiner index of the microbial community in the pelagic(0-10 cm,10-20 cm)(3.29,3.27)was slightly higher than that of the sub-bottom(20-30 cm)(3.17),and the index of the bottom(30-40 cm)was minimum(2.96),indicating the stability of the bacterial community structure.The microbial community structure showed a high degree of similarity(80%)at the pelagic(0-10 cm,10-20 cm)in different months,while the similarity between pelagic and bottom(20-30 cm,30-40 cm)was lower.Therefore,we could evaluate the sample space order through the similarity of the community structure.The diversity of microbial composition showed that the microflora in M.amblycephala intensive rearing period belonged to eight bacterial phyla:Proteobacteria 33.33%(β-,γ-,δ-Proteobacteria),Chloroflexi 19.05%,Bacteroidetes 14.29%,Cyanobacteria 9.52%,Acidobacteria 4.76%,Firmicutes 4.76%,Spirochaetes 9.52%,Nitrospirae 4.76%.The 16S rDNA clone library analysis indicated that there were lots of bacteria in the M.amblycephala intensive rearing pond sediments.The Proteobacteria which consisted mainly of δ-Proteobacteria was the dominant group in sediments.The results provided important information for selection of the beneficial bacteria and regulation of the micro-ecological environment in the M.amblycephala intensive rearing pond.